What is path length (l) in Beer-Lambert Law?

Path length (l) in the Beer-Lambert Law refers to the distance that light travels through the sample, typically measured in centimeters. It is an important factor in the calculation of absorbance since a longer path length increases the probability of light being absorbed by the sample. In most spectrophotometric measurements, a standard path length of 1 cm is used, but for more concentrated samples, a shorter path length may be used to avoid excessive absorbance.